The Hall Effect – Sensor Applications

The use of a Hall Effect sensor is key in measuring the magnetic field of an object, as well as understanding how it all works in the first place. While such a theory can be difficult to understand when you look at the scientific element of it all, it becomes clearer when you know what the effect is actually used for, and in. The bottom line is that the Hall Effect is vital in many everyday life uses.

We know that the Hall Effect is used to measure the power and size of a magnetic field, and can be used to power certain objects, e.g. compasses and engine ignition, but it is about more than that also. The sensor, e.g. the probe which is used to do the measuring, is at the crux of the entire subject. Without said sensor, there is no measurement to be taken, and no information to be found.

The Hall Effect sensor is a small probe which is ideal to be used in all different environmental conditions. If it’s raining, if the item needing to be measured is dirty or in mud, the sensor will still work. This is because the sensor is encased inside the head of the item, and therefore the interior isn’t exposed to the elements. For this reason, the Hall Effect sensor is a very commonly used piece of equipment.

But, with all of this in mind, what is a Hall Effect sensor used for?

There are many uses, and probably far too many to list, but the main ones include:

Position sensing

Position sensing may sound like a difficult to understand term, but it is actually simplistic. In this case, the sensor is used to detect a magnetic object. This is the most commonly used method for these types of sensors in the mainstream, away from the high-tech scientific world. In the case of a brushless DC motor, a Hall Effect sensor is used to detect the motor’s position, and in order to help move the transistors into the correct position and sequence. This helps the piece of equipment work correct. Current smartphones also use sensors, e.g. when detecting if the accessory cover case is open or closed.

Direct Current transformers (DC)

Contactless measurements are done with Hall Effects sensors with DC currents. In this case, the sensor doesn’t actually touch the equipment, and is mounted around the conductor, it the gap of the magnetic centre. This means the magnetic flux is easily measured in an accurate way.

Automotive fuel level indicators

Hall Effect sensors are used when measuring the fuel level within a vehicle. This is done by determining and sensing the position of an element, which is floating. A float magnet is often used in this case, or a rotating sensor.

Keyboard switch

A more high-tech use for a Hall Effect sensor comes in the use of the keyboard switch. A company called Honeywell, dating back to 1969, made use of the micro switch. This is something which is used in the Space Cadet keyboard on LISP machines, and While this is a rather scientific use, it is still a good example of the importance of the Hall Effect sensor’s uses.

As you can see, Hall Effect sensors are used for much more than simply measuring how much a magnetic field affects anything. From cars to compasses, engines to smartphones, the Hall Effect really does affect more than anyone ever realises. All of this goes to prove that the things you can’t see are sometimes more important than the things you can touch and visualise with your own two eyes.